Nonstationarity and reformation of high‐Mach‐number quasiperpendicular shocks: Cluster observations
Nonstationarity and reformation of high‐Mach‐number quasiperpendicular shocks: Cluster observations
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DOI：
10.1029/2006gl029095
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发表时间：
2007-03
影响因子：
5.2
通讯作者：
V. Lobzin;V. Krasnoselskikh;J. Bosqued;J. Pinçon;Steven J. Schwartz;M. Dunlop
中科院分区：
文献类型：
--
作者：
V. Lobzin;V. Krasnoselskikh;J. Bosqued;J. Pinçon;Steven J. Schwartz;M. Dunlop
给出了2001年1月24日07：05-07：09 UT，Cluster航天器穿越高马赫数（Mf = 5）准垂直（θBn = 81°）弓形激波层的一组实验数据。对磁场、电场起伏谱和离子分布的测量表明，激波是高度非平稳的。特别是，在不同航天器上测得的磁场分布彼此差异很大。在激波斜坡上游观测到的下移波的平均频率振荡的特征时间与质子回旋周期相当。此外，离子从冲击波的反射是突发性的，并且该过程的特征时间也与离子回旋周期相当。所有这些特征结合起来是支持激波阵面重组的第一个令人信服的实验证据。
A set of experimental data is presented for a high‐Mach‐number (Mf = 5) quasiperpendicular (θBn = 81°) bow shock layer crossed by Cluster spacecraft on 24 January 2001 at 07:05–07:09 UT. The measurements of magnetic field, spectra of electric field fluctuations, and ion distributions reveal that the shock is highly nonstationary. In particular, the magnetic field profiles measured aboard different spacecraft differ considerably from each other. The mean frequency of downshifted waves observed upstream of the shock ramp oscillates with a characteristic time comparable with the proton gyroperiod. In addition, the reflection of ions from the shock is bursty and a characteristic time for this process is also comparable with the ion gyroperiod. All of these features in conjunction are the first convincing experimental evidence in favor of the shock front reformation.